In the hills of the Dangs district of Gujarat, cut off from the world by the thick teak forests that cling to their slopes, Hindu extremists are waging a modern Inquisition, forcibly converting aboriginal peoples to what they have decreed is India's one true faith. Since Christmas, hundreds of Adivasis, the remnants of the tribes that once roamed all of India, have been forced to renounce Christianity and undergo a shudhi, or purification, ceremony at a hot springs at the town of Unnai. The conversion drive is the latest terror to be visited on the tiny Christian community. In the week after Christmas 22 mud-and-thatch prayer halls were attacked by Hindu extremists

The extremists justify the attacks - and the stoning of schools, desecration of icons and assaults on priests and nuns in 108 recorded acts of violence against Christians throughout the country last year - as spontaneous outbursts of anger against the relentless efforts of Christian missionaries.

But the accounts of villagers who were forced to undergo the ceremony and the saffron-robed sadhu (holy man) who has orchestrated the conversion campaign show that Hindu extremists allied to the nationalist Bharatiya Janata Party, which leads India's coalition government, are pursuing their efforts with a similar zeal.

'They said our Christian gods were demons and that they would burn down our houses,' said Umra Mohan Pawar, an old man in Jamuna Vihir, a village about 10 miles from Ahwa, the main town in the Dangs.

Like virtually all the 144,000 Dangs, Mr Pawar is an Adivasi. Largely confined to forest areas, the Adivasis traditionally worshipped the forces of nature, and were introduced to Christianity by missionaries last century.

Nobody knows how many Christians they produced. Leaders of the Catholic Church and Protestant denominations put the number as low as 12,000. The Hindu extremists claim that 40,000 Adivasis have become Christians, enticed by faith healing and false claims of salvation. Nationally Christians comprise 2.3 per cent of the population.

Mr Pawar said he and two dozen other villagers were bundled into jeeps by militants of the Hindu Jagran Manch (Hindu Awakening Movement).

They were taken to Unnai, where a temple has been built around a natural hot spring. Mr Pawar mimed the splashing of water over his head. 'Then they said: 'you are Hindus now',' he said.

He was also given a locket of the Hindu monkey god. I am not putting it on,' he said. 'I am staying a Christian.'

The struggle for souls is not confined to Gujarat, where Christians make up less than half a per cent of the population of 43 million. The extremists have launched a conversion drive in neighbouring Maharashtra state too.

On a larger scale, they are seeking to mobilise India's Hindus against the Congress leader, the Italian-born Roman Catholic Sonia Gandhi, whose party humiliated the BJP in the state elections in November.

Until violence broke out in the Dangs the authorities largely dismissed the attacks on Christians, arguing that no lives were lost and that the media and foreign powers were seeking to subvert the national interest.

Sensitive to the rising international criticism, however, the prime minister, Atal Bihari Vajpayee, visited the Dangs last weekend. Hours after he had left Hindus set fire to a village church at Dhuda

'Before Vajpayee came, there was a little peace, but now all types of incidents have happened,' said the Rev TV Gaikwad, the local convenor of the Church of North India, which groups mainstream Protestant denominations. He fears the violence will continue.

People in other villages tell the same story as Mr Pawar: threats and intimidation, followed by the ceremony at Unnai and a visit to the ashram in the town of Vaghai, presided over by a persuasive Hindu sadhu, Swami Aseem Anand. Then they return to their villages and set fire to the church.

The swami disclaims any connection to the converts - save to serve them a vegetarian lunch and to distribute lockets and pictures of the monkey god.

'It is not I who am doing this. The people of Dangs go on their own. The Hindu brothers keep on coming here and saying that our Christian neighbours want to become Hindu,' he said.

Mr Pawar's adoption of Christianity a few years ago, during the despair that followed the death of two of his four children, was as speedy as his arrival in the Hindu fold.

With a chuckle and an embarrassed shrug he mimed the splashing of water over his body, but this time laid a hand on his head in an imaginary blessing.

That simple action is telling of the tactics of the recent arrivals among the Christian missionaries, who have proved nearly as aggressive in their methods as Swami Aseem Anand.

'We pray to God to intervene in their life and we get their sickness cured,' said Solomon Swamidoss, a Baptist missionary. He estimates that he converted 300 people to Christanity on his six miles of territory between 1985 and 1994.